1. Field of the Invention
The present invention relates to a coupling adjusting structure for a double-tuned circuit which is suitably used for a TV tuner and the like.
2. Description of the Related Art
A configuration of a known coupling adjusting structure for a double-tuned circuit will be described with reference to FIG. 11. A printed circuit board 51 has a variety of electrical components (not shown) disposed thereon including first and second tuned circuits 52 and 53 formed side by side.
First and second coils 54 and 55 serving as a part of the first and second tuned circuits 52 and 53 have windings 54a and 55a formed by winding wires, and two pairs of fixing legs 54b and 55b disposed at the ends: of the windings 54a and 55a, respectively.
The first and second coils 54 and 55 are configured such that the windings 54a and 55a are mounted on the printed circuit board 51 in an upright manner while being close to each other, and the fixing legs 54b and 55b are passed through the printed circuit board 51 and soldered to corresponding conductive patterns (not shown) formed on the lower surface of the printed circuit board 51.
In the double-tuned circuit having such a configuration, an inductive coupling is adjusted by deforming free corresponding ends of the mutually opposing windings 54a and 55a of the first and second coils 54 and 55 in the opposing directions indicated by the arrows Z in the figure.
The known coupling adjusting structure for a double-tuned circuit is configured such that the windings 54a and 55a are disposed in an upright manner against the printed circuit board 51 so as to deform a part of each of the windings 54a and 55a of the first and second coils 54 and 55, respectively, giving rise to a problem in that the double-tuned circuit is tall.